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Nanotechnology in food and farming is inadequately regulated, say Australian researchers.

Rural sociologist Dr Kristen Lyons of Griffith University and colleagues present a survey of possible nano-applications in agriculture and food at the Rural Futures conference in Canberra this week.

"Despite significant investment from the agrifood sector in nanotechnologies, the need for nano-specific regulation in this area hasn't been recognised as a priority by the federal government," says Lyons.

She says the nano-agrifood industry will be worth more than US$20 billion by 2010, with heavy investment from several large international companies.

Lyons says one of the claimed agricultural benefits for nanotechnology is the development of more efficient methods of applying pesticides.

For example, creating nano-sized versions of pesticide molecules could lead to nanopesticide emulsions that are more stable, more toxic to pests and better absorbed into plants, she says.

But Lyons says the same characteristics that make nanopesticides desirable could also present new risks to humans or the environment.

For example, the ability for nanoparticles to penetrate the surface of plants may mean they also penetrate into edible parts of the crop, she says.

Or their added ability to dissolve may mean nanopesticides create new kinds of contamination in soils, waterways or the food chain.

Nanotechnology can also be used to create capsules containing pesticide toxins, says Lyons.

The capsules could be designed to release their contents in specific situations, such as inside the stomach of an insect.

Lyons says while these could give more controlled and effective delivery of pesticides, capsules could wash away and release their toxins into environments they weren't intended for, including the stomachs of other living organisms.

But Lyons says there are no nano-specific regulations so manufacturers may not be legally required to register nano versions of already approved pesticides.

She says the world's leading chemical company already sells a number of pesticide emulsions containing nanoparticles.

"What we don't know is whether they're for sale in Australia," she says.

Lyons says nanosensors are also being developed to provide real-time monitoring of farm nutrients, pH and moisture levels, as well as pests and pathogens.

She says in some cases these could be linked to nano-seed varieties with in-built pesticides that are released by remote computers linked to a GPS system.

These nanosensors may be scattered widely over farming landscapes causing a new form of "nanopollution", says Lyons.

Food applications

Lyons says nanotechnology is also being used in the food industry, for example, to encapsulate nutrients.

Some nano-structures could sense a person's nutrient requirements such as calcium or iron, and respond by making these nutrients available.

Lyons says some sources suggest there are as many as 300 nanofood products in the international markets and sales in nanofood and packaging were valued at US$5.3 billion in 2005.

The Food Standards Australia New Zealand website says while there is no evidence of adverse effects currently available, potential applications of nanotechnology in food could be a concern for health and environmental reasons.

The agency says it is keeping a watching brief on the food industry's use of nanotechnology.